So, you're trying to defeat Kidney failure on legendary difficulty, got it. =)

Hopefully something comes.

 

I do like a challenge 😕.

Considering my current condition even the doctors are somewhat confused, as I have very little symptoms. I'm tired, got low red blood cells, I've gain weight only in my stomach area, everything else I've lost muscle mass. But, my cup is half full. I'm looking forward to spring. I'm always cold.

I've survived many hard times so I'll survive this too.

BTW, I was bored and was reading about the shudder, did the op check the rear tire? I've heard it can wiggle and vibrate just enough to feel like a shudder.
Just a crazy suggestion.

 

So it appears as if this is the route I should try with my 2016. I replaced the spark plugs which were in dire need of replacement and some of my shudder went away. I still have some of it though.

 

I rotated the tires the other day just in case.

But its a decel shudder that happens even in neutral.
So its a reverse load on the drive train.

So, it quite possibly could be this spindle thing. I'll know more tomorrow when I get the grease in there. Its 30 out right now and the grease isn't here yet.

 

There is a lot. hahaha.

None of this is fun. My old truck is so easy compared to this.

 

Here's another useful video, for those who have a 2 piece rear driveshaft.

 

Thought I'd randomly pop in here and post that I pulled the driveshaft and went to inspect inside.
Blue grease down in the back.

I'm crossing my fingers for this being the culprit then.

It's such a weird issue too. Drove yesterday. Trip there, no vibration, no nothing.
Drove home and it was back.

So silly.

 

Greasing the output pinion did not fix the vibration.

was really hoping that was it. =\

 

<p>Sorry about your dad. Sounds like you inherited a good project though.</p><p>The 6R80 in the 2016 F150 has a well-documented torque converter clutch shudder issue. You are right that it is a TCC friction problem, not an internal trans failure. The shudder happens at light throttle around 35-55 mph when the TCC is trying to lock up. Ford put out service bulletins on this. The fix is a drain and refill with Motorcraft Mercon ULV fluid -- the original Mercon V that these came with does not have the right friction modifiers to keep the TCC from shuddering. Mercon ULV addressed it. A lot of people see it go away completely after one fluid change with the correct spec.</p><p>The friction modifier you added might help temporarily but Mercon ULV is the real fix. You do not need a flush -- just drain the pan, drop the filter, clean the pan, install new filter, and refill with Mercon ULV. About 7-8 quarts to do it right.</p><p>One thing worth separating out: if the vibration you feel is constant at all speeds and through the steering wheel, that sounds more like a front-end issue than the TCC shudder. Trans shudder is usually a specific sensation at light throttle in a narrow speed range. Constant vibration in the steering wheel points more toward a wheel bearing (even if new), driveshaft balance, or CV axle. Worth confirming which symptom is which before chasing the trans too hard.</p>

 

The only other thing I've not done is a spark plug swap.

But its not a front end issue.
And the steering wheel vibration isn't the main problem. you can feel it in the steering wheel, just like you feel the TQ slip issue as reported by many people who have the slip issue.

The feeling the truck gives is the shudder issue.
But the how and when it gives it is not lining up as well. Which makes it really weird.

With what's left/owed on the truck, its honestly not worth it for me to keep chasing this as I struggle to even think the truck is worth what is still owed to the bank for it.

 

Been noticing this on my 2016 i bought used last year. It had 75k on it, i bought it in july 2025....drove it till november with no issues, decided to drop the pan and change fluid and filter. Added the tube of modfier and it was good up until a month ago. Shudder is there....almost like lugging a manual transmission. I have no change in rpms when it happens. I also rest the adaptive tables. Still there, not horrible, but its defintely there. I just put it in sport mode most of the time. I'll have to keep an eye on it and maybe take it in before extended warranty runs out.

 

I had the rumble strip feeling in mine up until a couple months ago. I pumped 4 qts of old trans fluid out twice. through the dip stick/ fill hole. After the 1st fluid exchange the shudder/ rumble strip feeling were gone. I've got one left to do in that one I'll drop the pan and replace the filter. I didn't do any friction modifier just Motorcraft ATF. I'm at 107k now.

 

Looks like Ford is going to recall 2015-2017s

https://www.ford-trucks.com/forums/1...on-recall.html

 

Long shot, but did you check the 4 wheel drove actuator /motor??? Maybe it's stuck slightly engaged .